// Copyright 2010 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_VM_STATE_H_
#define V8_VM_STATE_H_

#include "src/allocation.h"
#include "src/counters.h"

namespace v8 {
namespace internal {

    // Logging and profiling.  A StateTag represents a possible state of
    // the VM. The logger maintains a stack of these. Creating a VMState
    // object enters a state by pushing on the stack, and destroying a
    // VMState object leaves a state by popping the current state from the
    // stack.
    template <StateTag Tag>
    class VMState {
    public:
        explicit inline VMState(Isolate* isolate);
        inline ~VMState();

    private:
        Isolate* isolate_;
        StateTag previous_tag_;
    };

    class ExternalCallbackScope {
    public:
        inline ExternalCallbackScope(Isolate* isolate, Address callback);
        inline ~ExternalCallbackScope();
        Address callback() { return callback_; }
        Address* callback_entrypoint_address()
        {
            if (callback_ == kNullAddress)
                return nullptr;
#if USES_FUNCTION_DESCRIPTORS
            return FUNCTION_ENTRYPOINT_ADDRESS(callback_);
#else
            return &callback_;
#endif
        }
        ExternalCallbackScope* previous() { return previous_scope_; }
        inline Address scope_address();

    private:
        Isolate* isolate_;
        Address callback_;
        ExternalCallbackScope* previous_scope_;
#ifdef USE_SIMULATOR
        Address scope_address_;
#endif
    };

} // namespace internal
} // namespace v8

#endif // V8_VM_STATE_H_
